In the field of rehabilitative therapy, as well as physical conditioning, exercise and training generally, various devices are known and used both for measuring force applied by an individual and for providing resistive force to facilitate exercise and therapy. These devices usually can function in either the dynamic or static modes but not both modes. Such devices generally are limited to very specific forms and amounts of applied force and generally have not provided both a variable, controlled dynamic resistance and a static mode for measuring applied force.
Our co-pending application Ser. No. 07/160,758, which is incorporated herein by reference, describes a device for use in rehabilitation testing and therapy as well as physical conditioning generally which measures isometrically force applied to the device from any of several directions, such as lifting, pulling or pushing.
U.S. Pat. No. 4,882,677 to Curran describes a combination disability analysis computer system and isometric strength testing device which includes means to calculate anthropometric and joint compression data and which compares actual and expected force.
U.S. Pat. No. 4,235,439 to DeDonno describes a friction exercise device utilizing a system of pulleys, brakes and hydraulic cylinders.
U.S. Pat. No. 373,942 to Page describes a coin-operated, strength testing machine in which a force is exerted against a simple system of cables and a rotary mechanical gauge.
U.S. Pat. No. 3,929,331 to Beeding describes an exercise device in which cable is wound around a pulley whose turning is opposed by springs.
U.S. Pat. No. 4,728,102 to Pauls describes a frictional resistance indicator in which force is applied and measured through a system of cables.
U.S. Pat. No. 3,589,193 to Thornton describes an electric ergometer for imposing work loads which includes a torque motor with controllable feed back loops for imposing variable resistance in response to applied force.
U.S. Pat. No. 3,397,884 to Blasi describes an isometric testing apparatus which uses spring scales to measure the force.
U.S. Pat. No. 3,550,449 to Henson describes a device based on sliding frictional resistance between a rope and a shaft.
U.S. Pat. No. 4,082,267 to Flavell describes a device which is specifically isokinetic (speed regulating).
U.S. Pat. No. 4,592,545 to Sagedahl describes a device which is an attachment for use on an isokinetic machine.
U.S. Pat. No. 4,355,635 to Heilbrun describes a device which is based on the specific design of an exercise apparatus which is motor driven by a variable speed motor and provides therapeutic manipulation for the disabled.
U.S. Pat. No. 3,851,874 to Wilkin describes a device for dynamic exercise whose main purpose is to provide vibration because it utilizes a square pulley. All claims are based on a "non-circular" pulley which is not isometric.
U.S. Pat. No. 4,678,184 to Neiger describes a device which is motor operated for concentric and eccentric exercise and is speed controlled (isokinetic).
U.S. Pat. No. 4,565,368 to Boettcher describes a device which is an attachment for isolating back motion on an isokinetic device and directly restrains the patient above and below the waist and is completely isokinetic (speed controlled).
As noted, however, the devices of the prior art have not generally provided a versatile device for both therapy, exercise and evaluation which has the capacity to function in both isometric and isoinertial modes, and which, in particular provides a lifting function in either mode.
It is accordingly, an object of the present invention to provide an isoinertial device which can function in both the static or dynamic modes to provide isometric evaluation of applied force and controlled, adjustable dynamic resistance in the isoinertial mode to applied lift force.
It is a further object of the present invention to provide an isoinertial lift device having an isometric function which permits computerized evaluation of user performance and which is provided with an automatic clutch mechanism to prevent sudden release of weights.